Art of distillation



Jan. 1, 1929.

W. K. LEWIS ET AL ART OF DIST ILLATION Original Filed Dec. 30. 1922 i iii? anon 01, MIRRENK LE WIS AND IVA THANJEL E. L COM/S 351 HA); (Flt/tuna Patented Jan. 1, 1929.

- UNITED STATES PATENT OFFICE.

WARREN K. LEWIS, OF NEWTON, MASSACHUSETTS, AND NATHANIEL E. LOOMIS, OF WESTFIELD, NEW JERSEY, ASSIGNORS TO STANDARD OIL DEVELOPMENT COMPANY,

A CORPORATION OF DELAWARE.

ART OF DISTILLATION.

Original application filed December 30, 1922, Serial No. 609,872. Divided and this application April 28, 1927. Serial No. 187,189.

The present invention relates to the art of distillation, particularly in connection with operations on materials which are subject to thermal decomposition unless the distillation is properly controlled. The invention will be fully understood from the following description, reference being had also to the accompanying drawing, in which The figure represents a side elevation partly in section, of one form of apparatus contemplated in the invention. a

The present types of vacuum stills have not shown as good results as could be desired, for the reason particularly, as we have found, that too much resistance is interposed in the path of the vapors and the effective vacuum realized at the surface of the vaporizing liq- -uid is correspondingly not what the pump efliciency would lead one to expect. In the case of decomposable materials, as for example lubricating-oil distillates, this results in increased decomposition or cracking, with a lowered viscosity and flash.

In proceeding in accordance with the present invention, We provide a suitable still or vaporizing receptacle for the liquid being heated in the example illustrated in the drawing, this taking the form of a cylindrical shell 1 mounted over a suitable heater chamber. Such still may be set up and used as an individual unit if desired, or more advantageously, as shown, a plurality, to the number desired, may be arranged to operate in a battery; in this latter case a flow line F having valves F and branch connections to and from the stills is provided for furnishing the fed and removing the residuum. A separate residuum pipemay be added if' desired and in the case of an individual still simple feed and residuum pipes may be used connecting directly to respective tanks. 1

In the top of the still means, is provided for condensing the vapors and taking away the condensate.-

This comprises a cooling or chilling coil 9 with connections 10' arranged to be supplied with a suitable cooling fluid and below the coil a drip deflector 12, and a collector pan 14 to catch the condensate and discharge by pipe 15 into a suitable receiver (not shown, for simplification) having vacuum connections for use when desired,

A conduit 20 leads from beyond the cooling zone to a vacuum pump (not shown, for simplification) and a manometer and thermometers are located on the still as desired.

In operation, liquid to be distilled is admitted from the feed tank in the case of an individual still or from the flow line in the case of a battery, and in continuous running as the distillation proceeds feed liquid is supplied as desirable by regulatin the valve.

'The residuum is withdrawn elther to the short and without constriction an efi'ective vacuum is realized through the system down to the liquid surface.

The path of the vapors is comparatively short and the cooling being controlled and restricted to a predetermined zone arranged to handle the condensate, refluxing run-back to the still maybe correspondingly avoided,

a matter'which is ofimportance in the comparatively low temperature operations with extreme vacua very low absolute pressures,

for example 25- mm. or less of mercury.

While in describing the invention, we have referred to certain specific details it will be' understood that this is for purpose of illustration and not :limitation, and the invention 1s to be regarded as limited only as defined in thefollowing claims in which it is our intention to claim all inherent novelty as broadly as the prior art permits.

The present application is a division of our co-pending application Serial No. 609,872.

We. claim: 1. In the distillation of high boiling oil, the improvement that comprises'distilllng a body of the oil by direct 'fire heat under verylow absolute vapor pressure and below a temperature. at which substantial cracking'occurs in the oil body, taking ed the vapors through a passage substantially without constriction between the surface of the oil and a condensingzone, preventing substantial drop in the temperature of the vapors until they approach said zone, whereby refluxing is and collecting the condensate tween the surface of the oil and a. condensing 1o formed'in said zone. zone, 'jacketing the. passage with a hot me- 2. Inthe distillation of high boiling oil, dium to avoid) substantial drop in the ten theimproy'ement that comprises distilling a perature of the vapors, thereby substantially 5 body of the oil by direct fire Best under very preventing refluxing; and collecting the conlow absolute vapor pressure, and below a temdensate formedin said zone. I

perature at which substantial cracking occurs in the oil body, passing'the vapors throug a WARREN K. LEWIS.

passage substantially without constriction be NATHANIEL E. LO OMIS. 

